Macheda has notched nine times in 12 appearances for Blues since his loan from Manchester United.
"I remember talking to some lads at Manchester United, a couple of coaches, a couple who are still playing, before we got him," Watson told the Birmingham Mail.
"I asked them what Kiko was like and the overall answer was 'scores goals'. Whether it is training or a game.
"Sometimes he will frustrate you, sometimes he will play on the shoulder and be offside, sometimes he won't hold the ball up like you want him to.
"But, at the end of the day, this game is about scoring goals, and stopping them at the other end. And he scores goals in abundance.
"The minute he robbed the left-back Saturday you fancied him to score, probably more so than anyone else in the squad."
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